This invention relates to a machine for applying labels to containers such as cylindrical cans having various diameters.
In one known type of labeling machine a wheel rotates about a vertical axis. Several shafts are equiangularly spaced about the wheel on a common circle. The shaft axes are parallel to the rotational axis of the wheel. There is a circular plate on the top of each shaft for supporting a container, such as a can that is to be labeled. Several gears are fastened on each shaft. A toothed belt is selectively brought into engagement with gears of the same size on each shaft for the purpose of changing the rotational speed of the shafts to facilitate applying labels to containers having different diameters. This is necessary because each container is orbited past a station wherein a longitudinal strip of glue is applied to it after which the container is carried past a stack of labels. The rotating container is rolled onto the surface of an exposed label which is picked up by adhesion to the glue stripe and carried forward to a station where the label is wrapped around the container. The toothed belt and gear arrangement for adjusting the rotational rates of the disks and the containers requires a construction wherein moving parts are out in the open to make it easy for servicing personnel to grasp and reverse or tilt the toothed belt. Thus, protection against environmental influences is hardly afforded. Moreover, reversal or tilting of the toothed belt is time consuming and inconvenient.
In another known type of labeling machine the rotating disks for the shafts therefor are connected with a planetary wheel which engages in a sun-wheel arranged concentrically to the rotary disks. The sun-wheel is supported rotatably and driven by means of a back-gearing arrangement with an adjustable rotating shaft and an exchangeable change-gear synchronously with the rotary disks. Different rates of rotation of the rotary disks are obtained by exchanging gears. One disadvantage of this arrangement is that an individual change-gear must be manufactured and held in stock for the various container diameters that the labeling must be able to handle. Besides changing gears, the rotating shafts must be adjusted in insure proper change-gear meshing with the sun-wheel. This is time consuming and requires substantial skill. It is not possible to securely enclose the gearing since engagement between the sun-wheel and change-gear must be observed.
In another known labeling machine there is a stationary lifting cam for the rotary plates. The rise and fall of the cam is converted into rotation of the plates through a coarse-thread-gearing. Planetary gearing sets the rotary plates into oscillating or rotational movement. The cam is comprised of several curved pieces which are individually exchangeable. Disadvantageously, a series of individual curved pieces must be made and held in stock for each container diameter that the labeling machine must accommodate.